1. Field of the Invention
The present invention relates to a printer control pictorial tool for use in setting up an automatic photo-printer to proper printing conditions. More particularly, the present invention relates to a printer control pictorial tool which enables setting up proper printing conditions in any kind of photo-printer.
2. Background Arts
An automatic photo-printer measures three color densities of an original to be printed and determines appropriate print-exposure times for three colors in accordance with the measured three color densities. To maintain the photo-printer in proper printing conditions that are relevant to the exposure determination, the printing conditions are checked and corrected prior to the practical printing. For this purpose, a sample print is made from a reference original having standard three color densities that are designed to represent standard customer's photographic originals forwarded to photofinisher for printing. The sample print is compared to a reference print that is previously made from the reference original under optimum conditions by a manufacturer.
A conventional reference original has a pattern consisting of a round gray center portion and a background, called Bull's eye. Usually, four control negative frames of the same pattern are recorded in series on a filmstrip at different exposure amounts to provide a printer control film. In addition to these frames, i.e., normal-, under-, over- and super over-exposed frames, the printer control film has an unexposed frame having no image recorded thereon, so as to represent a basic density of the photo film.
The normal-exposed control negative frame is used as the reference original. Generally, most customer's negatives are photographed in daylight, i.e., outdoors from 10 a.m. to 2 p.m., or under similar lighting conditions to the daylight, at proper exposure values determined based on the film speed, so that most negatives have normal image densities. Usually, human subjects occupy about one-third of the entire area of each negative frame, and the remaining portion, i.e. the background, is occupied by landscapes such as trees, sky, buildings, road and so forth. In principle, a mixed light of three color light components transmitted through a properly exposed negative is gray. Therefore, the reference original contains the round gray pattern or so-called eye portion.
A kit of printer control films of different film types are supplied in combination with their reference prints to photo-printer's users. The printer control films and the reference prints are called printer control tools in this field.
There have been printer control tools which use a pictorial full-color image such as portraits in place of the eye portion, in order to make it easy to check with the naked eye if color balance and densities of the sample print are proper or not. Also printer control tools having both a gray eye portion and a pictorial image are disclosed, for example, in JPA 9-26633. Hereinafter, those printer control tools containing a pictorial image will be called printer control pictorial tools.
Since the automatic photo-printer makes a sample print from a reference original at exposure times determined for three colors in accordance with three color densities of the reference original measured by a photometry device of the photo-printer, in the same way as in the practical printing, characteristics of the photometry device and algorithms for determining exposure times have influence on density and color balance of the consequent sample print.
Because different types of photo-printers have different photometry devices and different algorithms, the sample prints obtained from the conventional printer control pictorial tools are apt to be affected by the difference in the photometry device and the algorithm, especially by the differences in photometric range covered by the photometry section, that is, the range subjected to the photometry on each original frame, have a large influence on the quality of sample print. This is because photometric values and the algorithms for the exposure determination are affected by the layout of the full-color pictorial image, such as color arrangement and contrast.